The window we used is a type made especially for bathrooms; the frame is vinyl covered and the glass is tempered and frosted, for privacy and safety. It is recessed in the wall like any other window, but the marble sill is slightly angled so water rolls away.

Sonja,
As Katy stated, The window is vinyl with tempered glass.
The opening is double flashed with a flexible bituminous tape. This is a full frame window with integral nailing flange... this install is water tight inside and out with frame flashing for any condensed water vapor.

What color grout did you use on the basketweave floor tile? Thank you!